The present invention generally relates to color video signal transmission systems, and more particularly to a color video signal transmission system which converts a composite color video signal into a pseudo component coded signal having the form of a special component coded signal and having no chrominance subcarrier and transmits the pseudo component coded signal to a transmission medium.
Generally, when processing a composite color video signal in a video tape recorder (hereinafter simply referred to as a VTR), it is necessary to take into consideration the effects of time base deviation (jitter), frequency band and waveform distortion. The so-called direct FM recording system (or direct color processing system) employed in the VTR for broadcasting use copes with the above three points without compromise, but the color video signal must be frequency-modulated directly, and the FM color video signal must be recorded on and reproduced from a tape which is transported at such a speed that the relative speed between the tape and a head is in the range of 2 m/sec to 40 m/sec and high. As a result, there are problems in that the mechanism of the VTR must have a high precision, circuits of the VTR become of large scale, and a large quantity (length) of tape is required to carry out the recording and reproduction.
On the other hand, the so-called color under system is employed in the VTR for commercial or industrial use and in the VTR for home use. In this case, the relative speed between the tape and the head is in the order of a few m/sec and low. In addition, a luminance signal and a carrier chrominance signal are separated from the color video signal, and the luminance signal is frequency-modulated. The carrier chrominance signal is frequency-converted into a frequency band with a center frequency in the vicinity of 600 kHz to 700 kHz which is lower than that of a frequency band of the frequency modulated (FM) luminance signal. The FM luminance signal and the frequency converted carrier chrominance signal are frequency-division-multiplexed and recorded on and reproduced from the tape. For this reason, the problems of the VTR for broadcasting use are reduced according to the VTR for commercial or industrial use (or for home use).
The direct FM recording system and the color under system described before may be considered as being a kind of color video signal transmission system. But in the color video signal transmission system employing the color under system, there is a problem in that, out of the total information contained in the color video signal, the information which is actually transmitted is only in the order of 1/2 the total information. Therefore, because only approximately 1/2 the total information is transmitted, the VTR for home use and the like employing the color under system suffers problems in that the resolution of a reproduced picture is unsatisfactory and lacks sharpness and detail, and that the color resolving power is unsatisfactory.